One of the firms, Nevins & Associates, based in Maryland, said it would “launch an aggressive and comprehensive online campaign to eliminate the negative search results for UC Davis and the Chancellor through strategic modifications to existing and future content and generating original content as needed,” according to its contract, which was obtained by The Bee through a freedom of information request. Under the contract, signed in January 2013, more than two years after the protest, the university agreed to pay $15,000 per month for six months.

And that raises the question: Does this sort of thing work? In a word, no. Eliminating undesirable search results is not possible, said Danny Sullivan, an expert in search engine optimization. Mr. Sullivan is the founder of Marketing Land and Search Engine Land.

“I want to say it felt laughable,” he said of the contract. “It read like a document written from 1998.”

Dana Topousis, a university spokeswoman, said that the “increased investment in social media and communications strategy has heightened the profile of the university to good effect.”

Instead of zapping unfriendly news articles and commentary from the search results, the goal of such search scrubbing efforts is to create enough new content to push down the negative results to at least the second page of links in Google search results. Most people don’t dig beyond the first page, so having your own positive links bury the negative ones could dull their impact.

“It can be possible that you can make search results more positive for some queries, but it’s not guaranteed,” Mr. Sullivan said.

Nevins & Associates, which engineers responses for people and institutions that are subject to negative media attention, did not return a phone call or reply to an email seeking comment.

The contract with Nevins & Associates proposed a heavy reliance on Google platforms, especially Google+, the social network that, at the time, was considered an important cog in Google’s strategy. It encouraged Ms. Katehi to host video chats, known as “Hangouts,” and said staff members should identify “key-influencers” and “make connections as necessary.”

“We will interact as well as include and earn inclusion in their ‘Circles,’ ” it wrote, referring to the personal networks of Google+ users.

The second firm, Idmloco, of Sacramento, had more moderate goals in its June 2014 contract. Instead of wiping bad news away, it aimed to “achieve a reasonable balance of positive natural search results.” That firm was awarded $82,500 for a six-month contract.

Ms. Topousis said that the university hired an additional consultant last month to get advice on crisis management.